• Figure 3. Finger (blue) and non-finger (orange) touches in the unrestricted typing condition ( 1), showing space between hands, separate left and right spacebar areas, and evidence of forearms and heels of the hands resting on the screen. (N = 20)

isk feedback conditions ( 2 and 3). Here, we were able to do a more detailed analysis of typing patterns by using the one-to-one correspon- dence between touch events and letters in the presented text. Since participants were asked to cor- rect all errors they felt themselves make, typing speeds were slower (at 27 to 28 WPM) than in the unre- stricted condition. Unsurprisingly, as can be seen in Figure 4, participants were more
consistent in where they placed
their fingers when a visible key-
board was shown than when they
were asked to type on a blank
screen. Regardless of the key-
board condition, participants were
also less consistent in where they
touched their fingers for keys at the
outer edges of the keyboard (Q, A, Z,
P) than for keys in the middle. This
pattern suggests that increasing
the relative size of those outer-edge
keys may improve typing accuracy.

These findings provide insight into how we might redesign QWERTY keyboards to better support natural typing patterns on touchscreens. Beyond these general implications, however, we also observed that typing patterns varied greatly from one user to the next, particularly in the no-keyboard conditions ( 1 and 2). Personalization may therefore be critical in supporting touch typing with limited visual attention on touchscreens.

 

May + June 2012

interactions

3. asterisk feedback and a visible keyboard.

The two conditions without a visible keyboard ( 1 and 2) were designed to capture natural typing patterns. In the unrestricted condition ( 1), participants were unaware of spurious or missing touches, which mimicked an ideal touch-typing keyboard and allowed for the most natural typing possible.

In the asterisk feedback conditions (conditions 2 and 3), output for each non-space key press was in the form of an asterisk (*), similar to what one sees when entering a password (see Figure 1). The asterisk feedback provided the user with some indication that their input had been received without the system having to actually determine what letter the user had intended to press—a serious challenge when no keyboard was shown and participants could type wherever they liked! Participants corrected any typing errors they felt they had made with a backspace right-to-left swipe gesture so the asterisks and spaces lined up with the presented text. This requirement enabled a one-to-one mapping during analysis between touch events and letters from the presented text.

Redesigning the QWERTY keyboard.

In the unrestricted typing condi-
tion ( 1), in which participants could
assume their input was correct
without having to worry about acci-
dental or incorrect key presses, typ-
ing speeds were on average 59 words
per minute (WPM). While this speed
was slower than the 85 WPM we saw
when we gave these same partici-
pants physical keyboards, it was still
quite fast for touchscreen text input.

Personalizing Touchscreen Keyboards Based on our exploratory study, we found the idea of an adaptive, personalized keyboard to be compelling. In this second phase of the research, we designed and evaluated two novel adaptive keyboards for a Microsoft Surface. Both keyboards begin as a standard rectangular layout (Figure 5a) but over